- Adjuvant therapy: Patients receive oral capecitabine twice a day and oral erlotinib hydrochloride once a day for 5½ weeks. Patients also undergo concurrent radiotherapy 5 days a week for 5½ weeks. Beginning 6 weeks later, patients receive gemcitabine hydrochloride IV on days 1, 8, and 15 and oral erlotinib hydrochloride once daily on days 1-28. Treatment with gemcitabine hydrochloride and erlotinib hydrochloride repeats every 28 days for 4 courses.